1. Field of the Invention
The subject invention relates to firearms and laser systems and, more specifically, to methods and apparatus for assisting the aiming of a firearm, and in particular to methods and apparatus for assisting the aiming of a firearm with a light beam from a laser.
2. Disclosure Statement
This disclosure statement is made pursuant to the duty of disclosure imposed by law and formulated in 37 CFR 1.56(a). No representation is hereby made that information thus disclosed in fact constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends on uncertain and inevitably subjective elements of substantial likelihood and reasonableness, and inasmuch as a growing attitude appears to require citation of material which might lead to a discovery of pertinent material.
For over seventy years, proposals have been made for assisting the aiming of firearms with light beams or light spots on targets. Reference may, for instance, be had to U.S. Pat. No. 894,306, which proposes clamping of an elongate light source, including a small electric incandescent lamp and a projection lens, to the barrel of a handgun, U.S. Pat. No. 1,452,651, which proposes clamping of a flashlight to a handgun barrel, U.S. Pat. Nos. 1,826,004 and 2,844,710 which propose clamping of an electric incandescent lamp and battery unit to a handgun, and U.S. Pat. Nos. 3,010,019 and 3,974,585 which also propose employment of electric incandescent lamps for providing aiming marks on firearm targets or on an optical sight.
Practical limitations on light output intensity and coherence achievable with incandescent lamps have relegated the utility of such proposals to nightsight or target finder equipment of rather limited range.
Aim assistance electric incandescent lamps also have found a limited application in reticle image projectors of complex computing sights, as may be seen from U.S. Pat. Nos. 2,660,794 and 2,693,031. Apart from such special applications, the use of electric incandescent light aiming assists for firearms appears to have become restricted to aim assessment apparatus, as seen in U.S. Pat. No. 3,508,833.
Further proposals were spawned by the development of laser diodes comparable in size and ruggedness to small incandescent light bulbs (see U.S. Pat. No. 3,867,764). The utility of laser diodes as aiming devices was, however, generally limited to marksmanship trainer, boresight alignment, weapon simulator and similar applications, as may, for instance, be seen from U.S. Pat. Nos. 3,633,285, 3,782,832, 3,898,747, 3,938,262 and 3,995,376.
The success of gas discharge lasers in the surveying instrument field illustrated, for instance, by U.S. Pat. Nos. 3,533,700, 3,619,069, 3,667,849 and 3,823,313, similarly spawned proposals to use that type of laser in weapon aiming systems. As apparent from U.S. Pat. No. 4,026,054, an early proposal of this type structured a laser aiming system in the manner of firearm telescope sights, seen, for instance, in U.S. Pat. Nos. 870,272, 1,641,019, 2,510,289, 2,597,466 and 3,153,856, and also in French Pat. No. 492.773 by Albert Amigues and Louis Huet, issued Apr. 2, 1919.
A subsequent proposal, apparent from U.S. Pat. No. 4,079,534, suggested housing of the laser tube in a sighting apparatus attachment for firearms. Unlike shooting simulation systems having a laser mounted on a stationary support (see U.S. Pat. No. 3,904,204), proposals which suggested attachment of a laser tube to the firearm manifested a serious concern that the laser aiming system would be rendered useless by recoil forces resulting, for instance, in a misalignment of laser cavity end mirrors or breakage of the laser tube. Accordingly, proposals such as shown in the above mentioned U.S. Pat. Nos. 4,026,054 and 4,079,534 suggested the use of heavy shock mounting structures employing a laser head carriage slidable on a guide track, biased by compression springs and cushioned by a pneumatic buffer device. In practice, such a mounting structure considerably increases the bulk and expense of the particular weapons, while exposing same to a need for increased maintenance and danger of aiming inaccuracy.
In the transit instrument field, it has been proposed, as apparent from U.S. Pat. No. 3,796,496, that a laser plummet level unit be securely bolted down and that the flow of current to its laser tube be interrupted in response to undue physical disturbance of the instrument which might disturb the direction of the laser beam. Of course, such a proposal would not be practical with weapon aiming systems, since they would expose the user of the weapon to the danger of loosing sight of the target. Also impractical would be the provision of a gaseous discharge flash tube directly behind the barrel of a firearm, as was proposed in U.S. Pat. No. 3,294,401 for target game purposes.
In consequence, the development of laser aiming systems for firearms became stagnated in a search for effective shock mounting systems.